Clean gas injector system for reactor chamber

ABSTRACT

An improved Novellus Speed clean gas reactor chamber is described. An evacuation port of the Novellus SPEED Chamber is at one location in the chamber to remove injected cleaning gas from the chamber and there is a single input for cleaning gas connection into the chamber. In accordance an improvement a plurality of clean gas injectors is positioned on an adapter in the chamber and connected to the single input gas connection for distributing the cleaning gas in the chamber with the injectors spaced away from the evacuation port. The adapter is a U-shaped adapter and is positioned in the chamber with the adapter connected at the base to the single input gas connection. The adapter has two semicircular branch legs extending in opposite directions about the chamber to free ends that are connected to gas injectors. The free ends with the injectors are located in the chamber almost on the opposite end of the chamber from the evacuation port. Each of the two branch legs includes a second injector midway along the branch legs between the free ends and point of the branch to provide four injectors to evenly distribute the clean gas in the chamber.

FIELD OF INVENTION

[0001] This invention relates to clean gas injector system for a reactorchamber.

BACKGROUND OF INVENTION

[0002] The current clean gas injector on a Novellus HDP SPEED Chamberconsists of a single injector to deliver the cleaning gasses. Thechamber includes a base and a ceramic dome in form of a bell jar and isadapted to receive a semiconductor wafer at one port and is used todeposit fluorinated silicate glass (FSG, a dielectric) on the wafer. Italso gets everywhere in the chamber including the inside of the ceramicdome and chamber walls. The system has an in-situ cleaning system thatsends NF3 gas through a single clean gas injector to clean the chamberof the FSG.

[0003] The chamber and some walls are cleaned unevenly in this NovellusHDP SPEED Chamber system as illustrated by the sketch in FIG. 1.Referring to the sketch of FIG. 1 the chamber system 10 includes thedome or bell jar 12 over the chamber base 11. A single injector 13enters the base 11 of the chamber 10 at the same end as the vacuum pumpport 15. The cleaning gas flows through the injector and flows into thedome as illustrated by arrow 16. The vacuum port 15 is at the same endof the chamber 10 as the injector 13. The flow of the gas is illustratedby arrow 16. The flow is up from the injector 13 opening into the dome12 and evacuated down on the through the vacuum port 15. The gas flow ismostly in the direction of the arrow 16 so that the clean gas flow ismostly on the injector and the vacuum end of the chamber 10. The resultof this is an uneven cleaning rate of the reactor chamber 10 includingbase and chamber walls including the dome. The uneven rate of cleaningcauses buildup of aluminum fluoride in the chamber and presents particleproblem for deposition. It also results in over etching on the reactorand dome walls near the injector end. It is desirable to improve thein-situ cleaning the Novellus HDP SPEED Chamber and similar chambers.

[0004] Novellus has developed a system that is called “Toggle Clean.”Toggle Clean has two injectors that enter the reactor from orifices inthe floor of the reactor. The purpose of these injectors is to alternategas flow through them so that deposition in the injector tubes iscleaned. The new design flows gasses through multiple (3+) cleaninjectors simultaneously, providing more uniform gas flow and allowing amore robust clean.

SUMMARY OF INVENTION

[0005] In accordance with one embodiment of the present invention animproved clean gas system includes providing in the chamber an injectorat a location remote from the evacuation port.

[0006] In accordance with another embodiment of the present inventionclean gasses are distributed more evenly throughout the chamber bymultiple clean injectors distributed around the chamber and away fromthe evacuation port.

DESCRIPTION OF DRAWING

[0007]FIG. 1 illustrates a prior art Novellus system with a singleinjector.

[0008]FIG. 2 illustrates a first embodiment of the present inventionusing one injector remote from the exhaust port.

[0009]FIG. 3 illustrates a second embodiment of the present inventionusing two injectors.

[0010]FIG. 4 illustrates a third embodiment of the present inventionusing four injectors.

[0011]FIG. 5 illustrates the manifold adapter of FIG. 4 and theconnection of the adapter to the Novellus clean gas supply.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0012] In accordance with one embodiment of the present invention asillustrated in FIG. 2 the Novellus SPEED Chamber flow is improved bymoving the injector 13 to the end opposite the evacuation port 15 usinga curved extender pipe 14 extending the line from the current injectorport 13 to the evacuation port at other end of the chamber 10. The flowis more of a parabolic flow as illustrated by arrow 18 providing moreuniform cleaning. The extender pipe 14 extends around the inner base ofthe chamber 10 to the opposite end of the chamber 10.

[0013] The directly opposite end of chamber from the original positionof the injector port 13 and evacuation port 15 in the Novellus HDP SPEEDchamber is the access port to receive the wafer to be processed into thechamber so the placement of the injector 13 and the extender pipe 14 isnot such that the injector 13 is on the directly opposite end of thechamber from the evacuation port 15. Since the directly opposite end isnot free to easily put the injector 13 a dual injector system is used tomore evenly distribute the cleaning gas.

[0014] Referring to FIG. 3 there is illustrated a dual injector systemin chamber 10 according to a second embodiment of the present invention.Two injectors 13 a and 13 b are connected at the free ends of a U-shapedmanifold adapter 14. The two injectors 13 a and 13 b are placed oneither side of the wafer access port. The U-shaped manifold adapter 14is connected at the base 21 to the original input injector port 13 ofthe single injector and at the free ends of branch legs 14 a and 14 b tothe injectors 13 a and 13 b. The injectors 13 a and 13 b are by theadapter 14 placed on the opposite end of the chamber 10 from theevacuation port 15 located near the base 21 where the adapter 14branches off by branch legs 14 a and 14 b to the injectors 13 a and 13b.

[0015] Referring to FIG. 4 and 5 there is illustrated an improved systemwith four injectors that is the preferred embodiment of the presentinvention and provides the most even cleaning. In this embodiment thethere are four injectors 31-34 equally distributed about the chamber 10to provide more uniform gas flow with gap at the wafer access port. Theinjectors 31-34 are fed gas from the single clean gas input port that isconnected to a base 35 of a U-shaped manifold adapter 30 that branchesinto two semicircular tubes or branch legs 37 and 39 at the base 35. Theadapter 30 has a first branch leg 37 with an end injector 31 at the freeend of branch leg 37 and has a midpoint injector 32 located midway alongthe branch leg 37 between end injector 31 and the branch leg 37connection at the base 35. The second branch leg 39 has at the free endthe end injector 33 and has a midpoint injector 34 located midway alongbranch leg 39 between the end injector 33 and the branch leg 39 inputconnection at the base 35. The gas injectors 31-34 are pointed up 60degrees from horizontal pointing to center of the circle. The injectorand adapter are made of thicker high grade aluminum to overcome the heatin the chamber. The injectors 31-34 are ¼ outside diameter and ⅛ insidediameter. The adapter 30 is made ½ outside and ¼ inside diameter.

[0016] At the U-shaped manifold adapter base 35 branching point of theadapter 30 is a connecting section of pipe 36 that extends to a flange41 as illustrated in FIG. 5. A pipe 43 extends through the NovellusSpeed Chamber wall surface has a flange 45. A clamped junction 40 isprovided using this flange 45 that is connected through the SpeedChamber walls and flange 41. The clamped junction 40 includes an O-ringassembly 47 between the flanges 41 and 45 and a clamp assembly 51. TheO-ring assembly 47 includes an aluminum inner sealing ring 48, a Kalrezor Chemraz O-ring 49 and a protective aluminum outer pressure ring 50.The outer protective ring 50 protects the Kalrez or Chemraz O-ringmaterial from the plasma in the chamber. The whole assembly 47 isclamped together using a modified Nor-Cal KF Clamp 51. Kalrez is amaterial sold by DuPont and Chemraz is a Material sold by Greene Tweed.The end of pipe 43 is connected to the Novellus SPEED Chamber singleclean gas supply which is near the pump evacuation port 15.

[0017] Although the system and method of the present invention has beendescribed in connection with the preferred embodiment, it is notintended to be limited to the specific form set forth herein, but on thecontrary, it is intended to cover such alternatives, modifications, andequivalents, as can be reasonably included within the spirit and scopeof the invention as defined by the appended claims.

1. An improved clean gas system for a reactor chamber comprising: anevacuation port at one location in the chamber to remove injectedcleaning gas from the chamber and an injector at a location remote fromthe evacuation port for injecting the cleaning gas.
 2. An improved cleangas system for a reactor chamber comprising: an evacuation port at onelocation in the chamber to remove injected cleaning gas from thechamber; a single input cleaning gas connection into said chamber; and aplurality of clean gas injectors in said chamber connected to saidsingle input gas connection for distributing the cleaning gas in thechamber with the injectors spaced away from the evacuation port.
 3. Theclean gas system of claim 2 wherein said plurality is four.
 4. The cleangas system of claim 2 wherein said plurality is two.
 5. The clean gassystem of claim 2 including a U-shaped adapter located in said chamberwith the adapter connected to said single input gas connection andhaving two branch legs extending in opposite directions about thechamber to free ends that are connected to gas injectors and the freeends are remote from the evacuation port.
 6. The clean gas system ofclaim 5 wherein each of the two branch legs includes a second injectormidway between the free ends and point of the branch to more evendistribute the clean gas in the chamber.
 7. An improved Novellus Speedclean gas reactor chamber comprising: an evacuation port at one locationin the chamber to remove injected cleaning gas from the chamber; asingle input cleaning gas connection into said chamber; and a pluralityof clean gas injectors in said chamber connected to said single inputgas connection for distributing the cleaning gas in the chamber with theinjectors spaced away from the evacuation port.
 8. The clean gas systemof claim 7 including a U-shaped adapter located in said chamber with theadapter connected to said single input gas connection and having twosemicircular branch legs extending in opposite directions about thechamber to free ends that are connected to gas injectors and the freeends are remote from the evacuation port.
 9. The clean gas system ofclaim 8 wherein each of the two branch legs includes a second injectormidway between the free ends and point of the branch to more evenlydistribute the clean gas in the chamber.
 10. The clean gas system ofclaim 7 wherein said plurality is four.